CN108233789B

CN108233789B - Leading angle controller

Info

Publication number: CN108233789B
Application number: CN201710513204.9A
Authority: CN
Inventors: 李明硕
Original assignee: Hyundai Motor Co; Kia Motors Corp
Current assignee: Hyundai Motor Co; Kia Corp
Priority date: 2016-12-12
Filing date: 2017-06-29
Publication date: 2023-02-03
Anticipated expiration: 2037-06-29
Also published as: US20180167003A1; US10326388B2; KR102654914B1; KR20180067029A; CN108233789A

Abstract

The invention provides a lead angle controller, comprising: a position sensor configured to detect a position of a rotor of the BLDC motor; a lead angle control unit configured to determine a lead angle based on the detection signal and output a time for compensation of the lead angle as a lead angle control signal; a phase current converter configured to output a phase current conversion signal based on the detection signal and the lead angle control signal, wherein the phase current conversion signal determines a phase current step size of a stator of the BLDC motor; and a signal holder configured to hold the detection signal and the lead angle control signal and supply the detection signal and the lead angle control signal to the phase current converter at a predetermined timing when one of the detection signal and the lead angle control signal from the position sensor is changed.

Description

Leading angle controller

Technical Field

The invention relates to a lead angle controller.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Generally, among direct current motors having an electronic rectifying unit, a brushless direct current (BLDC) motor, which is a motor formed by replacing a commutator and a brush that are in mechanical contact with each other, has advantages of low electromagnetic noise and mechanical noise and long lifespan. With the improvement of device performance, reduction of weight and thickness, simplification of structure, extension of life, and development of parts or materials for semiconductor technology, the brushless dc motor has made a great progress and is widely used in various fields such as household appliances, information communication equipment, vehicles, and medical equipment.

Such brushless dc motors generally comprise a rotor as a permanent magnet and a stator as a stationary winding, in particular a three-phase stator. The position of the rotor is detected by a position sensor, such as a hall sensor, and a voltage is repeatedly and alternately applied to the stator depending on the detected position of the rotor, thereby operating the brushless dc motor.

When the rotor is rotated and the brushless dc motor is operated, the same effect is produced as when the wire is moved in the magnetic field. Also, a counter electromotive force is generated in the stator as an induced electromotive force, and therefore a current flows in the stator, and a voltage corresponds to a difference between the counter electromotive force and an applied voltage.

Therefore, for a desired operation of the brushless dc motor, the voltage should be repeatedly and alternately applied to the stator, i.e., the phase of the stator should be changed simultaneously with the signal detection of the hall sensor. However, a point in time at which a line current flows in the stator is relatively delayed due to the influence of the line inductance of the motor, compared to a point in time at which the phase of the stator is switched. In particular, the larger the inductance, the higher the rotational speed of the motor, and the larger the delay angle of the phase current, which may result in a decrease in the efficiency and torque of the brushless dc motor.

Disclosure of Invention

We have found that it is preferable to convert the phase current at an advance angle of a predetermined angle α before the time point of phase conversion when operating the brushless dc motor. The angle α is referred to as a "lead angle" and may be sized based on the resistance, inductance, and speed of the motor.

In order to control the lead angle in the related art, there have been the following methods: the lead angle is controlled by detecting a phase difference between an input signal and an output signal, and an amount of the lead angle is estimated by a Phase Locked Loop (PLL) that maintains a frequency of the output signal at a predetermined level by controlling a voltage controlled oscillator depending on a rotation speed of the motor, and there is a method of controlling information related to the lead angle by estimating the lead angle by curve fitting. Further, a lead angle controller has been disclosed in korean patent application laid-open No. 10-2015-0159499 to the inventor (entitled "lead angle controller"). The lead angle controller includes: an objective function derivation unit calculating a lead angle for compensating for a delay of phase current conversion of phase conversion of the plurality of stators, according to a rotation speed of the BLDC motor; and an encoder determining a point of time at which the lead angle is controlled in the phase conversion step by counting a number of phase conversion pulses, which is a number of pulses counted during the phase conversion step, and by deriving a number of lead angle pulses, which is a number of pulses corresponding to the lead angle calculated from the objective function.

The lead angle controller in the related art determines a switching time point of phase current by combining a plurality of hall sensor signals and a lead angle control signal for compensating a lead angle, but the hall sensor signals and the lead angle control signal are not precisely synchronized, and thus a glitch (glitch) is generated. This burr causes an undesirable motor output, thereby reducing the output torque of the motor or causing torque fluctuations.

The present invention provides a lead angle controller which can suppress generation of burrs when hall sensor signals and lead angle control signals are not precisely synchronized during phase current conversion of a motor based on the hall sensor signals for a rotor position in the motor and the lead angle control signals for determining a compensation time point of a lead angle.

An aspect of the present invention provides a lead angle controller, including: a position sensor configured to detect a position of a rotor of a brushless direct current (BLDC) motor; a lead angle control unit configured to determine a lead angle based on a detection signal from the position sensor, and output a time for compensation of the lead angle as a lead angle control signal; a phase current converter configured to output a phase current conversion signal for determining a phase current step (step) of a stator of the brushless dc motor based on the detection signal from the position sensor and the lead angle control signal; and a signal holder for holding a previous detection signal and a previous lead angle control signal from the position sensor when one of the plurality of detection signals from the position sensor and the lead angle control signal are changed, and then supplying the detection signal and the lead angle control signal from the position sensor to the phase current converter at a predetermined timing.

The signal holder may be a trigger configured to input the detection signal of the position sensor and the lead angle control signal and hold a value input by the control pulse for a predetermined time.

The flip-flop may be a D flip-flop configured to output and hold a value input at a rising edge or a falling edge of a control pulse having a predetermined frequency.

The position sensor may be a hall sensor configured to sense an S pole or an N pole on a rotor of the brushless dc motor.

The phase current converter may output a phase current conversion signal for determining a preset phase current step size to an inverter that provides a phase current to the brushless dc motor, based on the detection signal of the position sensor and the advance angle control signal.

Another aspect of the present invention provides a lead angle controller, including: a position sensor configured to detect a position of a rotor of a brushless direct current (BLDC) motor; a lead angle control unit configured to determine a lead angle based on a detection signal from the position sensor, and output a time for compensation of the lead angle as a lead angle control signal; a phase current converter that outputs a phase current conversion signal for determining a phase current step size of a stator of the brushless dc motor based on a detection signal from the position sensor and the advance angle control signal; and a flip-flop configured to input the detection signal of the position sensor and the lead angle control signal to output to an input of the phase current converter at one of a rising edge and a falling edge of a control pulse having a predetermined frequency, and hold a previous output until a subsequent rising edge or falling edge is generated in the control pulse.

With the lead angle controller, the rotor position detection signal and the lead angle control signal of the BLDC motor as a reference for phase current conversion can be synchronized, and therefore, the glitch can be suppressed.

In addition, with the lead angle controller, since the burr is suppressed, it is possible to eliminate distortion of the phase current supplied to the BLDC motor and the counter electromotive force of the BLDC motor. Accordingly, the torque waveform of the BLDC motor, which is expressed as a multiple of the counter electromotive force and the current, is improved, which may help to reduce torque ripple and improve driving stability.

Further, with the lead angle controller, as the torque ripple is reduced, noise and vibration of the BLDC motor can be reduced, and the efficiency of the BLDC motor can be improved by enhancing the torque performance.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

In order that the invention may be well understood, various embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram schematically illustrating a lead angle controller;

fig. 2 and 3 are views showing an example when a burr that can be removed by the lead angle controller is generated;

FIG. 4 is a timing diagram comparing the operation of a lead angle controller with a related art lead angle controller;

fig. 5 is a waveform diagram illustrating characteristics of a BLDC motor due to a lead angle controller without a method of deburring; and

fig. 6 is a waveform diagram showing characteristics of a BLDC motor due to a lead angle controller through which burrs are removed.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

Fig. 1 is a block diagram schematically illustrating a lead angle controller in some embodiments of the present invention.

Referring to fig. 1, a lead angle controller in some embodiments of the present invention may include: a position sensor 11 that detects a position of a rotor of the brushless direct current (BLDC) motor 10; a lead angle control unit 30 that determines a lead angle based on the detection signal from the position sensor 11 and outputs a compensated time point of the determined lead angle as a lead angle control signal; a phase current converter 50 that outputs a phase current conversion signal for determining a phase current step size of the stator of the brushless dc motor 10 based on the detection signal from the position sensor 11 and the lead angle control signal; and a signal holder holding a previous detection signal and a previous lead angle control signal from the position sensor when at least one of the detection signal and the lead angle control signal from the position sensor is changed, and then supplying the detection signal and the lead angle control signal from the position sensor to the phase current converter 50 at a predetermined point of time.

The BLDC motor 10 may include a stator and a rotor. For example, the stator may be a three-phase (U, V, W) stator, may be arranged at intervals of 120 degrees, and may operate as a magnetic pole (i.e., N pole or S pole) depending on the direction in which current flows in the stator. Here, the BLDC motor may rotate the rotor in a two-phase excitation manner, i.e., in a manner that only two phases among three phases (U, V, W) are excited and the remaining one phase is not excited. That is, the BLDC motor 10 may rotate the rotor in a 6-step phase conversion manner that selectively generates a potential difference of two phases of the three-phase (U, V, W) stators.

Although in the above description, the BLDC motor includes three phases (U, V, W) and the phases are switched in six steps according to the excitation types (U +, U-, V +, V-, W +, W-) of the three-phase (U, V, W) stator, the phase switching steps of the stator may be changed according to the number of stators. For example, in the case where 6 or more phase stators are provided, the phases of the stators may be switched in 12 steps.

As described above, the BLDC motor 10 can rotate the rotor by switching the phases of the stators, but the BLDC motor 10 must excite two-phase stators of three-phase (U, V, W) stators according to the rotation state of the rotor, and thus it is desirable to make information about the rotation state of the rotor clear.

For example, in the case where the S-pole of the rotor is not accurately positioned between the U-phase stator excited at the + potential and the W-phase stator excited at the-potential by the phase conversion step, the rotor may exhibit irregular rotation when the stators are converted to the subsequent phase conversion step, or may be rotated in reverse when it is rotated. Therefore, by precisely finding out the rotation type of the rotor, the BLDC motor 10 can maintain the rotation of the rotor by switching the phase of the rotor to the next step after the rotation of the rotor is stopped.

As described above, the BLDC motor 10 may necessarily include a position sensor for detecting a rotation state of the rotor and achieving accurate rotation of the rotor based on the rotation state. The position sensor is not particularly limited as long as it can determine the rotation state of the rotor, and for example, a hall sensor 11 capable of sensing the stimulation of the S pole or the N pole of the rotor may be generally used.

The hall sensor 11 may convert a stimulation signal sensed from the rotor into an electrical signal and transmit the electrical signal to an inverter that applies a current to the stator. The hall sensor 11 may be designed to sense the N pole or S pole of the poles of the rotor, and it may be a variable state that can be freely changed by a designer of the hall sensor 11, but for convenience of describing the present invention, it is shown here that the hall sensor 11 is designed to sense the N pole of the rotor. In particular, the hall sensor 11 may be disposed between three-phase (U, V, W) stators, exemplified here as three-phase (U, V, W) stators, and disposed between the three-phase (U, V, W) stators.

The rotor may be rotated by switching the phases of the three-phase (U, V, W) stator, and in this case, the hall sensor 11 located at a position facing the N pole of the rotating rotor may sense the N pole of the rotor. For example, N poles of the rotor may be sensed by hall sensors at both sides of the V-phase stator in the phase conversion step, and the N poles of the rotor may be sensed by hall sensors positioned between the V-phase stator and the W-phase stator in the subsequent phase conversion step.

As described above, the N pole of the rotor may be sensed by the hall sensor 11, and a signal detecting the N pole of the rotor by the hall sensor 11 may be converted into an electric signal and transmitted to the inverter 20. The inverter 20 may apply a current to the stator to excite the stator according to the transmitted electrical signal. Accordingly, the phase current of the stator is converted by the current applied from the inverter, thereby rotating the rotor.

The detection of the N pole of the rotor by the hall sensor 11 can be understood as the completion of the phase transition of the plurality of stators. In each phase conversion step, the rotor is rotated by phase conversion of the three-phase (U, V, W) stator, and when the N pole of the rotating rotor is sensed by the hall sensor 11, it can be understood that the rotation of the rotor is ended in the corresponding phase conversion step, and then the phase conversion step is changed to another phase conversion step, so that the phase of the stator is converted again, and the rotation of the rotor can be maintained. Therefore, the detection of the N pole of the rotor by the hall sensor 11 is understood as the completion of the phase transition of the stator.

Further, the hall sensor 11 may detect the rotation speed of the BLDC motor 10. In detail, the hall sensor 11 may sense the rotation type of the rotor in each phase shifting step of the stator, and thus the hall sensor 11 may simply sense the rotation speed of the rotor, i.e., the rotation speed of the BLDC motor 10, by deriving the rotation of the rotor and a required rotation time.

The technique described with respect to sensing the rotational speed of the rotor using the hall sensor 11 is well known in the related art and thus will not be described in detail.

In order to keep the rotor rotating, i.e., to keep the BLDC motor 10 operating, it is required that the inverter 20 continuously converts the phase current of the stator based on the electric signal from the hall sensor 11, and for this reason, the inverter 20 receives the electric signal, i.e., the phase conversion completion signal of the stator, from the hall sensor 11 and applies a current to the stator to be excited by the phase conversion, which may be considered as a desired operation of the BLDC motor 10.

However, when a current is applied to the stator to be excited by phase switching by the inverter 20, an action of disturbing a change in magnetic flux (i.e., inductance) around or through the stator receiving the current is generated in the stator. Therefore, the current to be applied to the stator to be excited, i.e., the phase current conversion, is delayed. The higher the current frequency, the larger the inductance. This causes an increased delay of the phase current with respect to the phase transformation point of the stator, and the delay of the phase current may cause a reduction in efficiency and torque performance of the BLDC motor 10.

Therefore, when the BLDC motor is operated to prevent the performance degradation of the BLDC motor 10 due to the delay of the phase current conversion of the phase conversion of the stator, a method of controlling the lead angle is desired.

The lead angle is set at a time point when a current is applied to operate the BLDC motor 10, and it is possible to sufficiently compensate for a delay of phase current of phase inversion of the stator by controlling a phase current inversion time point of the stator by means of control of the lead angle when operating the BLDC motor 10.

A lead angle controller has been disclosed in korean patent application laid-open No. 10-2015-0159499 to the inventor (entitled "lead angle controller"). The lead angle controller includes: an objective function derivation unit calculating a lead angle for compensating for a delay of phase current conversion of phase conversion of the plurality of stators, according to a rotation speed of the BLDC motor; and an encoder determining a time point at which the lead angle is controlled in the phase conversion step by counting a number of phase conversion pulses, which is a number of pulses counted during the phase conversion step, and by deriving a number of lead angle pulses, which is a number of pulses corresponding to the lead angle calculated from the objective function.

In some embodiments of the present invention, the lead angle control unit 30 may be understood as including the concept of an object function derivation unit and an encoder disclosed in korean patent application laid-open No. 10-2015-0159499. In addition, all other types of lead angle controllers that derive a lead angle using a method of deriving a lead angle other than the method of controlling a lead angle disclosed in korean patent application laid-open No. 10-2015-0159499 and output a compensation time of a lead angle may be used as the lead angle control unit 30 of the present invention.

The phase current converter 50 may control phase current conversion of the stator by controlling a current applied to the stator to be excited by phase conversion of the BLDC motor 10. The phase current transformer 50 may control phase current transformation based on the lead angle control signal provided from the lead angle control unit 30 and a signal from the position sensor 11 (i.e., hall sensor) on the BLDC motor 10.

For example, the phase current converter 50 may output a phase current conversion signal for determining a phase current step (predetermined) to the inverter 20 by combining the signal from the position sensor 11 and the advance angle control signal. The inverter 20 may include a plurality of switching devices for generating a current of each phase, and two switching devices may be provided for each phase, so that a phase current may be determined by alternately turning on/off the two switching devices of each phase. The phase current switching signals provided for each of the two switching devices of each phase may be represented as U +, U-, V +, V-, W +, and W-.

The phase current converter 50 may receive the detection signal of the position sensor 11 and the lead angle control signal from the signal holder 40.

When the detection signal of the position sensor 11 and the lead angle signal are not changed, the signal holder 40 holds the previous detection signal of the position sensor and the previous lead angle signal for a predetermined time, and supplies the changed position sensor detection signal and the changed lead angle control signal to the phase current converter 50 at the predetermined time.

That is, even if the detection signal of the position sensor 11 and the lead angle control signal are not synchronized but partially changed, the signal holder 40 holds and outputs the previous detection signal of the position sensor 11 and the previous lead angle control signal to the phase current converter 50 so that the phase current step is not changed, and after a predetermined amount of time, the detection signal of the position sensor 11 and the lead angle control signal are simultaneously output to the phase current converter 50. Accordingly, the lead angle controller in some embodiments of the present invention can reduce the glitch caused by the inability to synchronize the detection signal of the position sensor 11 with the lead angle control signal.

Fig. 2 and 3 are views showing examples when a burr that can be removed by a lead angle controller is generated in some embodiments of the present invention.

In fig. 2 and 3, "phase" represents a phase current step size, "PDC" represents a lead angle control signal, "hall sensors" represent rotation angle detection signals of the BLDC motor output from a plurality of hall sensors, and "phase sequence" represents a phase current conversion signal determined based on the lead angle control signal and the position detection signal. Further, signals "0" and "1" represent the disabled state and the enabled state of the signals, respectively.

Referring first to fig. 2, in step (step) 1, when the advance angle control signal is enabled and H2 of the hall sensor is enabled, the phase current-converted signals output from the phase current converter 50 are 0, 1, and 0 for U +, U-, V +, V-, W +, and W-, respectively. In this case, even if the hall sensor signal is maintained at the hall sensor signal specified in step 1, the lead angle control unit 30 enables the lead angle control signal so as to output the phase current change signal first in step 2 to compensate for the lead angle, step 2 being a step subsequent to step 1.

In a desired operation, when step 2 is entered, in the lowermost row of the table shown in fig. 2, the advance angle control signal is disabled, H2 and H1 of the hall sensor are enabled, and it is assumed that phase current change signals of 0, 1 and 0 for U +, U-, V +, V-, W + and W-are sequentially output from the phase current converter 50, as when the advance angle control signal is enabled in step 1. However, when a desired operation is not performed, the lead angle control signal output from the lead angle control unit 30 is disabled first, and the hall sensor signal is maintained as the hall sensor signal in step 1, the phase current converter 50 generates an undesired output, that is, outputs a phase current conversion signal output when the lead angle control signal is disabled and only the signal from the hall sensor H2 is enabled. This operation of the lead angle controller results in glitches.

Fig. 3 shows the situation when the hall sensor signal is first changed or the advance angle control signal in step 1 is enabled, after which the advance angle control signal is disabled. In this case, the phase current converter 50 still outputs an undesired phase current conversion signal causing a glitch between step 1 and step 2.

As described above, the signal holder 40 is provided in various embodiments of the present invention to eliminate the cause of the burr.

As described above, even if the detection signal of the position sensor 11 is not synchronized with the lead angle control signal but partially varies, the signal holder 40 holds and transmits the previous detection signal of the position sensor 11 and the previous lead angle control signal to the phase current converter 50 so that the phase current step is not changed, and after a predetermined amount of time, the detection signal of the position sensor 11 and the lead angle control signal are simultaneously output to the phase current converter 50. That is, even if at least one of the detection signal (hall sensor signals) of the position sensor 11 and the lead angle signal is first changed, it is not immediately reflected, and the previous signal is maintained for a predetermined time, and then the detection signal of the position sensor 11 and the lead angle control signal, which are input after a predetermined amount of time has elapsed, are supplied to the phase current converter 50. That is, the signal holder 40 holds the previous position sensor detection signal and the previous advance angle control signal for a delay time, so that all signals required for the phase current converter 50 to output the phase current conversion signal can be changed. Further, after the delay time has elapsed, the signal holder 40 simultaneously supplies all the change values of the detection signal of the position sensor 11 and the lead angle signal to the phase current converter 50, so that it is possible to reduce the burr caused by the inability to synchronize the detection signal of the position sensor 11 with the lead angle control signal.

In some embodiments of the present invention, the signal holder 40 may be a flip-flop. In particular, the signal holder 40 may include a plurality of D-flip-flops provided for each of a plurality of detection signals of the position sensor 11 and the lead angle control signal, and the D-flip-flops may be operated by a common Control Pulse (CP).

The D flip-flop is a means for holding an input for a predetermined time using a control pulse, and may be composed of a plurality of logic devices. That is, the D flip-flop is a device that outputs data input at a rising edge (or a falling edge) of a control pulse. D flip-flops are well known in the art and therefore will be well understood by those skilled in the art to implement the present invention even though not described with reference to the accompanying drawings.

Fig. 4 is a timing diagram comparing the operation of the lead angle controller in some embodiments of the present invention with a related art lead angle controller.

Referring to fig. 4, when the detection signal of the position sensor and the lead angle control signal are input to the phase current converter 50 while the phase current state of the first step is changed to the phase current state of the second step, a burr is generated between the first step and the second step.

In contrast, in some embodiments of the present invention, even at the time point T1 at which at least one of the detection signal from the position sensor 11 and the lead angle control signal is changed, the phase current of the first step size may be maintained, and at the time point T3 at which the first rising edge is shown in the control pulse CP of the D flip-flop after the time point T1, the detection signal of the position sensor 11 and the lead angle control signal may be supplied to the phase current converter 50 through the signal holder 40 as the D flip-flop. That is, the signal holder 40 holds the detection signal and the lead angle control signal supplied to the position sensor 11 of the phase current converter 50 in the previous first step, while the glitch is generated in the related art, and provides sufficient time for all of the detection signal and the lead angle control signal of the position sensor 11 to change within the time points T1 to T3. As a result, all of the detection signal of the position sensor 11 and the lead angle control signal are changed and then simultaneously transmitted to the phase current converter 50.

The control pulse CP may be appropriately determined in consideration of an error of the detection signal of the position sensor 11 and the time point at which the lead angle control signal changes. Further, considering that an error of a time point when the detection signal and the lead angle control signal are actually changed is very short in the BLDC motor, by setting a large frequency for the control pulse CP, an effect of removing the burr and compensating the lead angle can be enhanced.

Fig. 5 is a waveform diagram illustrating characteristics of the BLDC motor due to lead angle control without a method of removing burrs, and fig. 6 is a waveform diagram illustrating characteristics of the BLDC motor due to the lead angle controller removing burrs through the lead angle controller in some embodiments of the present invention.

Comparing fig. 5 and 6, it can be seen that the waveforms of the phase current supplied to the BLDC motor and the back electromotive force of the BLDC are seriously distorted during the method of removing the burr (fig. 5). However, when the method of removing the burrs (fig. 6) is applied, it can be seen that the distortion of the waveforms of the phase current supplied to the BLDC motor and the back electromotive force of the BLDC is significantly reduced. The torque of the BLDC motor can be expressed as a multiple of the back electromotive force and the current, and thus the torque waveform is improved, which helps to reduce torque ripple and improve driving stability. Further, as the torque ripple is reduced, noise and vibration of the BLDC motor may be reduced, and the efficiency of the BLDC motor may be improved by improving torque performance.

The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

1. A lead angle controller comprising:

a position sensor configured to detect a position of a rotor of the brushless DC motor;

a lead angle control unit configured to determine a lead angle based on a detection signal from the position sensor, and output a time for compensation of the lead angle as a lead angle control signal;

a phase current converter configured to output a phase current conversion signal based on the detection signal from the position sensor and the lead angle control signal, wherein the phase current conversion signal determines a phase current step size of a stator of the brushless dc motor; and

a signal holder configured to:

holding a previous detection signal from the position sensor and a previous lead angle control signal for a predetermined time when one of the plurality of detection signals from the position sensor and the lead angle control signal are changed; and is provided with

The detection signal from the position sensor and the lead angle control signal are supplied to the phase current converter at a predetermined timing.

2. The controller according to claim 1, wherein the signal holder is a trigger configured to input the detection signal of the position sensor and the lead angle control signal, and hold a value input by a control pulse for a predetermined time.

3. The controller according to claim 2, wherein the flip-flop is a D flip-flop configured to output and hold a value input at a rising edge or a falling edge of a control pulse having a predetermined frequency.

4. The controller of claim 1, wherein the position sensor is a hall sensor configured to sense an S pole or an N pole on a rotor of the brushless dc motor.

5. The controller according to claim 1, wherein the phase current converter is configured to output a phase current conversion signal for determining a predetermined phase current step to an inverter, wherein the inverter is configured to provide a phase current to the brushless dc motor based on the detection signal of the position sensor and the lead angle control signal.

6. A lead angle controller comprising:

a phase current converter configured to output a phase current conversion signal based on the detection signal from the position sensor and the lead angle control signal, wherein the phase current conversion signal is configured to determine a phase current step size of a stator of the brushless dc motor; and

a flip-flop configured to:

inputting a detection signal of the position sensor and the lead angle control signal;

outputting an input signal to the phase current converter at a rising edge or a falling edge of a control pulse having a predetermined frequency, wherein the input signal is a detection signal of the position sensor and the lead angle control signal; and is provided with

The previous output is held until a subsequent rising or falling edge is generated in the control pulse.

7. The controller of claim 6, wherein the position sensor is a Hall sensor configured to sense an S pole or an N pole on a rotor of the brushless DC motor.

8. The controller of claim 6, wherein the phase current converter is configured to output a phase current conversion signal for determining a predetermined phase current step size to an inverter, wherein the inverter is configured to provide phase current to the brushless DC motor based on the detection signal of the position sensor and the lead angle control signal.